Delay Explicit GC from the SystemServer. (25020a6f) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/BinderInternal.java

+108 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,14 @@ import android.util.EventLog;
		import java.lang.ref.WeakReference;
		import java.util.ArrayList;

		import java.util.concurrent.Callable;
		import java.util.concurrent.ExecutionException;
		import java.util.concurrent.ExecutorService;
		import java.util.concurrent.Executors;
		import java.util.concurrent.FutureTask;
		import java.util.concurrent.TimeUnit;
		import java.util.concurrent.TimeoutException;
		import java.lang.Object;
		/**
		* Private and debugging Binder APIs.
		*
		@@ -34,6 +42,13 @@ public class BinderInternal {
		static ArrayList<Runnable> sGcWatchers = new ArrayList<>();
		static Runnable[] sTmpWatchers = new Runnable[1];
		static long sLastGcTime;
		/* Maximum duration a GC can be delayed. */
		private static final int GC_DELAY_MAX_DURATION = 3000;
		/**
		* Maximum number of times a GC can be delayed since the
		* original request.
		*/
		private static final int POSTPONED_GC_MAX = 5;

		static final class GcWatcher {
		@Override
		@@ -99,7 +114,100 @@ public class BinderInternal {
		Runtime.getRuntime().gc();
		}

		/**
		* TimerGc Callable : Wait for a certain time, and execute the BinderGc.
		* Set the postponed count to 0.
		*/
		public static class TimerGc implements Callable<Void> {
		private long waitTime;
		public TimerGc(long timeInMillis){
		this.waitTime=timeInMillis;
		}
		@Override
		public Void call() throws Exception {
		Thread.sleep(waitTime);
		forceGc("Binder");
		postponedGcCount = 0;
		return null;
		}
		}

		/**
		* lastGcDelayRequestTime records the time-stamp of the last time
		* a GC delay request was made.
		*/
		static long lastGcDelayRequestTime = SystemClock.uptimeMillis();
		static TimerGc timerGcInstance = null ;
		static FutureTask<Void> futureTaskInstance = null ;
		static ExecutorService executor = Executors.newFixedThreadPool(1);
		static int postponedGcCount = 0;
		static Object delayGcMonitorObject = new Object();

		/**
		* modifyDelayedGcParams : Call from the framework based on some special Ux event.
		* like appLaunch.
		*
		* 1. If this is the first time for the trigger event, or, if there is no scheduled
		* task, create a new FutureTaskInstance, and set the lastGcDelayRequestTime.
		* This will be used by forceBinderGc later.
		*
		* 2. If the postponed iterations hit a maximum limit, do nothing. Let the current
		* task execute the gc. If not,
		*
		* a. Set the start time.
		* b. Increment the postponed count
		* c. Cancel the current task and start a new one for GC_DELAY_MAX_DURATION.
		*/
		public static void modifyDelayedGcParams() {
		long nowTime = SystemClock.uptimeMillis();
		synchronized(delayGcMonitorObject) {
		if ((futureTaskInstance != null) && (postponedGcCount != 0)) {
		if (postponedGcCount <= POSTPONED_GC_MAX) {
		futureTaskInstance.cancel(true);
		if (futureTaskInstance.isCancelled()) {
		lastGcDelayRequestTime = nowTime;
		postponedGcCount++;
		timerGcInstance = new TimerGc(GC_DELAY_MAX_DURATION);
		futureTaskInstance = new FutureTask<Void>(timerGcInstance);
		executor.execute(futureTaskInstance);
		}
		}
		} else {
		lastGcDelayRequestTime = nowTime;
		timerGcInstance = new TimerGc(GC_DELAY_MAX_DURATION);
		futureTaskInstance = new FutureTask<Void>(timerGcInstance);
		}
		}
		}

		/**
		* Modified forceBinderGc. The brief algorithm is as follows --
		*
		* 1. If no futureTaskInstance has been initiated, directly force a BinderGc.
		* 2. Check for the duration since the last request, and see if it was within the
		* last GC_DELAY_MAX_DURATION secs. If yes, we need to delay the GC until
		* GC_DELAY_MAX_DURATION.
		* 3. If there is a task scheduled (postponedGcCount != 0), we merely prevent this GC,
		* and let the GC scheduled execute.
		* 4. If no task is scheduled, we schedule one now for (GC_DELAY_MAX_DURATION - touch duration),
		* and update postponedGcCount.
		*/
		static void forceBinderGc() {
		synchronized(delayGcMonitorObject) {
		if (futureTaskInstance != null) {
		long lastGcDelayRequestDuration = (SystemClock.uptimeMillis() - lastGcDelayRequestTime);
		if (lastGcDelayRequestDuration < GC_DELAY_MAX_DURATION) {
		if (postponedGcCount != 0)
		return;
		futureTaskInstance.cancel(true);
		timerGcInstance = new TimerGc(GC_DELAY_MAX_DURATION - lastGcDelayRequestDuration);
		futureTaskInstance = new FutureTask<Void>(timerGcInstance);
		postponedGcCount = 1;
		executor.execute(futureTaskInstance);
		return;
		}
		}
		}
		forceGc("Binder");
		}
		}

services/core/java/com/android/server/am/ActivityStackSupervisor.java

+5 −0

Original line number	Diff line number	Diff line
		@@ -103,6 +103,7 @@ import com.android.internal.widget.LockPatternUtils;
		import com.android.server.LocalServices;
		import com.android.server.am.ActivityStack.ActivityState;
		import com.android.server.wm.WindowManagerService;
		import com.android.internal.os.BinderInternal;


		import java.io.FileDescriptor;
		@@ -2641,6 +2642,10 @@ public final class ActivityStackSupervisor implements DisplayListener {
		}
		}
		mPm.cpuBoost(2000 * 1000);

		/* Delay Binder Explicit GC during application launch */
		BinderInternal.modifyDelayedGcParams();

		if (DEBUG_TASKS) Slog.d(TAG, "No task found");
		return null;
		}